Specific Aims: Motion Control Inc. proposes to develop a rugged, electric-powered work-hand/gripper for electric arm prostheses. This new terminal device (TD) will be lighter in weight, can be used in more extreme environments, and will offer more versatile gripping shapes than existing electric TDs. Motion Control is perfectly positioned to build upon the recent development of the Motion Control (MC) Hand, which includes a 2-speed drive producing 25 lb. of pinch force, and the highly functional Flexion Wrist. Background: The modern electric arm prosthesis has significant advantages over body-powered devices: freedom from uncomfortable control cables (also allowing greater work envelope), very high pinch force (requiring little effort), and more natural appearance. However, existing electric work TDs are not durable enough for many work environments. The effort: During Phase I, Motion Control will design and build engineering models of two versions of the proposed Work-Hand. One will integrate hand-like shapes molded in rugged plastic, used without a protective hand shell. The second version will implement hook-type TD fingers, for a very lightweight and versatile alternative. Water-resistant housings for the drive will be developed for both versions of the TD, which will be interchangeable with nearly all electric hands currently in use.